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JulijaS [17]
3 years ago
12

What are some reasons the human population increased greatly in the past couple hundred years?

Chemistry
1 answer:
Lana71 [14]3 years ago
7 0

Answer:

Explanation:

This rapid growth increase was mainly caused by a decreasing death rate, and particularly an increase in average human age. By 2000 the population counted 6 billion heads, however, population growth started to decline after 1965 because of decreasing birth rates.

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23) A common reaction that occurs in cells is shown here. In the presence of oxygen, a glucose molecule is combusted to form car
maw [93]

Answer:

C

Explanation:

add them together and multiply by 2

5 0
2 years ago
Name: _________________ Temperature o fwater_25_degreecent.YOU MUST SHOW ALL CALCULATIONS TO RECEIVE CREDIT FOR THEM! DATA ANALY
Anton [14]

Answer:

1. 0.02 M

2. 0.01 M

3. 4×10⁻⁶

Explanation:

We know that V₁S₁ = V₂S₂

1.

Concentration of HCl = 0.05 M

end point comes at = 10 ml

So, concentration of OH⁻(aq) = [OH⁻(aq)] ⇒ (0.05 × 10) ÷ 25 ⇒ 0.02 M

2.

2mol of OH⁻(aq) ≡ 1 mole of Ca²⁺(aq)

[Ca²⁺] = 0.02 ÷ 2 = 0.01 M

3.

K_{sp} = [Ca²⁺(aq)] [OH⁻(aq)]²

Ca(OH)₂ (aq) ⇄ Ca²⁺ (aq) + 2OH⁻ (aq)

K_{sp} = [0.01 × (0.02)²] = 4×10⁻⁶

4.

If reaction is exothermic which means heat energy will get evolved as a result temperature of the reaction media will get increased during the course of the reaction. If temperature is externally increased, the reaction will go backward to accumulate extra heat energy.

5.

K_{sp} value describes the solubility of a particular ionic compound. The higher the K_{sp} value, the higher the Solubility will be.

6.

This may be due to uncommon ion effect. The process of other ions (K⁺ or Na⁺) may increase the solubility

4 0
3 years ago
How many H2O molecules are in 183.2 grams of H20 gas?
jek_recluse [69]

Answer: There are 61.24 \times 10^{23} molecules present in 183.2 grams of H_{2}O gas.

Explanation:

Given: Mass = 183.2 g

Number of moles is the mass of substance divided by its molar mass.

As molar mass of water is 18 g/mol. Therefore, moles of H_{2}O are calculated as follows.

Moles = \frac{mass}{molar mass}\\= \frac{183.2 g}{18 g/mol}\\= 10.17 mol

According to the mole concept, there are 6.022 \times 10^{22} molecules present in one mole of a substance.

Hence, molecules present in 10.17 moles are calculated as follows.

10.17 mol \times 6.022 \times 10^{23}\\= 61.24 \times 10^{23}

Thus, we can conclude that there are 61.24 \times 10^{23} molecules present in 183.2 grams of H_{2}O gas.

6 0
3 years ago
How many grams of solid nickel will be plated if an aqueous nickel(II) sulfate solution is electroplated over 10.5 min with a co
Anna71 [15]

Answer:

613 mg

Explanation:

$Ni^{2+} + 2e \rightarrow Ni(s)$

Number of fargday's  $=\frac{It}{96500}$

Here, I = 9.20 A

        t = 10.5 min

          = 10.5 x 60 seconds

So, $\frac{It}{96500}$

  $=\frac{3.20 \times 10.5 \times 60}{96500}$

 = 0.0208 F

Here, 2e, 2F

2F = 1 mol of Ni

$0.0208 \ F = \frac{0.0208}{2} = 0.0104 \ mol \ Ni$

1 mol = 59 gm of Ni

0.0104 mol = 59 x0.0104 gm Ni

                    = 0.613 gm Ni

                    = (0.613 x 1000 ) mg of Ni

                    = 613 mg of Ni

3 0
2 years ago
The bobsled is an event in the winter Olympics. In this event, each sled and its riders speed down an icy track. Which factor(s)
goldenfox [79]

Answer:

Speed and Mass

3 0
2 years ago
Read 2 more answers
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